After four years and 250,000 deaths, the Syrian civil war is getting even more complicated. And now the U.S. and Russia are stepping up their roles in the country -- though on opposing sides.

There's a lot at stake in Syria. More civilians getting killed on a daily basis. Millions of refugees fleeing to other countries. And the threat of ISIS setting up even more terror hotbeds in the volatile country.

U.S. gives rebels tons of ammo

The U.S. is ramping up efforts to support Syrian rebels fighting Bashar al-Assad's regime. This week, U.S. military cargo planes gave 50 tons of ammunition to rebel groups in northern Syria, using an air drop of 112 pallets.

C-17s, accompanied by fighter escort aircraft, dropped small arms ammunition and other items like hand grenades in Hasakah province in northern Syria to a coalition of rebels groups vetted by the U.S., known as the Syrian Arab Coalition.

All pallets successfully were recovered by friendly forces, a U.S. official said.

But the United States' $500 million program to train an equip Syrian rebels has come under heavy criticism. This summer, Defense Secretary Ash Carter admitted the U.S. had only trained about 60 rebel fighters.

The low numbers are blamed on a strict vetting process that includes ensuring the fighters are committed to combat ISIS, as opposed to the Assad regime, and passing a counter-intelligence screening.

Russia tries to bolster Assad with airstrikes
Russia surprised the world two weeks ago when it launched its first airstrikes in Syria. Russian officials said they were coordinating with Assad and targeting ISIS and other terrorists.

"Our task is to stabilize the legitimate government and to create conditions for a political compromise ... by military means, of course," President Vladimir Putin told the state-run Russia 24 TV.

But after more than 100 airstrikes later, analysts have said Russia's focus clearly isn't on ISIS targets, but rather Syrian rebels seeking Assad's ouster.

EU: Russian airstrikes must end

The European Union Foreign Affairs Council isn't buying Russia's claims that ISIS is its primary target in Syria.

"The recent Russian military attacks that go beyond Dae'sh and other UN-designated terrorist groups, as well as on the moderate opposition, are of deep concern, and must cease immediately," the group said, referring to another name for ISIS.

"The EU condemns the excessive, disproportionate and indiscriminate attacks that the Syrian regime continues to commit against its own people. The Assad regime bears the greatest responsibility for the 250.000 deaths of the conflict and the millions of displaced people."

Courtesy CNN